Chapter 8. Capacity upgrades 205
Draft Document for Review April 7, 2004 6:15 pm 6947ch08.fm
CBU can only add CPs to an existing z990 server, but note that CPs can assume any kind of
workload that could be running on IFLs, zAAPs, and ICF processors at the failed system or
systems. z/VM, Linux, Java code and CFCC (for Coupling Facility partitions) can also run on
CPs.
When the CBU activated capacity is no longer required, its removal is nondisruptive. If CBU is
activated on a z990 server, other hardware upgrades/MES are restricted. With exception of
memory and channels, LIC-CC enabled features such as CPs, ICFs, IFLs, and zAAPs can be
ordered but not enabled, until the CBU upgrade is deactivated.
The CPs that can be activated by CBU come from the available spare PUs on any installed
book of the designated z990 server. So the number of CBU features (FC 7800), one for each
“stand-by” CP, that can be ordered is limited by the number of spare PUs on the server. Some
examples:
򐂰A 2084-B16 server with 8 CPs (no IFLs, ICFs, or zAAPs) has 8 available spare PUs
available; this server can have up to 8 CBU features.
򐂰A 2084-B16 server with 8 CPs and 2 zAAPs (no IFLs or ICFs) has 6 available spare PUs
available; this server can have up to 6 CBU features.
򐂰A 2084-C24 server with 12 CPs, 2 IFLs and 1 ICFs has 9 available spare PUs available;
this server can have up to 9 CBU features.
Note that CBU can add CPs via LIC-CC only and the z990 server must have the proper
number of books installed to allow the required upgrade by LIC-CC. CBU changes the
server’s software model (3xx) but cannot change the z990 server model (2084-xxx).
A CBU contract must be in place before the special code that enables this capability can be
loaded on the customer’s server. CBU features can be added to an existing z990 server
nondisruptively.
The installation of the CBU code provides an alternate configuration that can be activated in
the face of an actual emergency. Five CBU tests lasting up to 10 days each, and one CBU
activation lasting up to 90 days for a real disaster/recovery, are usually allowed in each CBU
contract.
A CBU system normally operates with a “base” PU configuration having a pre-configured
number of additional spare PUs reserved for activation as CPs in case of an emergency. One
CBU feature is required for each “stand-by” CP that can be activated. A CBU activation
enables the total number of CBU features installed.
The base CBU configuration must have sufficient memory and channels to accommodate the
potential needs of the large CBU target server. When capacity is needed in an emergency,
the customer can activate the emergency CBU configuration with the reserved spare PUs
added into the configuration as CPs. It is very important to ensure that all required functions
are available on the “backup” server(s), including CFLEVELs for Coupling Facility partitions,
as well as cryptographic and connectivity capabilities.
This upgraded configuration is activated temporarily and provides additional CPs above and
beyond the server’s original, permanent configuration. The number of additional CPs is
predetermined by the alternate configuration, which has been stated in the CBU contract.
Important: The CBU capability can coexist with On/Off CoD enablement. Both CBU and
On/Off CoD LIC-CC can be installed on a z990 server, but the CBU activation and On/Off
CoD activation are mutually exclusive.